For years, the conventional wisdom has been that suicide terrorists are rational political actors, while suicidal rampage shooters are mentally disturbed loners. But the two groups have far more in common than has been recognized.

Over the last three years, I have examined interviews, case studies, suicide notes, martyrdom videos and witness statements and found that suicide terrorists are indeed suicidal in the clinical sense — which contradicts what many psychologists and political scientists have long asserted. Although suicide terrorists may share the same beliefs as the organizations whose propaganda they spout, they are primarily motivated by the desire to kill and be killed — just like most rampage shooters.

In fact, we should think of many rampage shooters as nonideological suicide terrorists. In some cases, they claim to be fighting for a cause — neo-Nazism, eugenics, masculine supremacy or an antigovernment revolution — but, as with suicide terrorists, their actions usually stem from something much deeper and more personal.

There appears to be a triad of factors that sets these killers apart. The first is that they are generally struggling with mental health problems that have produced their desire to die. The specific psychiatric diagnoses vary widely, and include everything from clinical depression and post-traumatic stress disorder to schizophrenia and others forms of psychosis. The suicide rate was 12.4 per 100,000 people in the United States in 2010 (the highest in 15 years). Suicide is relatively rare, but it is rarer still in most Muslim countries. This is a very limited pool from which most suicide terrorists and rampage shooters come.

The second factor is a deep sense of victimization and belief that the killer’s life has been ruined by someone else, who has bullied, oppressed or persecuted him. Not surprisingly, the presence of mental illness can inflame these beliefs, leading perpetrators to have irrational and exaggerated perceptions of their own victimization. It makes little difference whether the perceived victimizer is an enemy government (in the case of suicide terrorists) or their boss, co-workers, fellow students or family members (in the case of rampage shooters).

The key is that the aggrieved individual feels that he has been terribly mistreated and that violent vengeance is justified. In many cases, the target for revenge becomes broader and more symbolic than a single person, so that an entire type or category of people is deemed responsible for the attacker’s pain and suffering. Then, the urge to commit suicide becomes a desire for murder-suicide, which is even rarer; a recent meta-analysis of 16 studies suggests that only two to three of every one million Americans commit murder-suicide each year.

The third factor is the desire to acquire fame and glory through killing. More than 70 percent of murder-suicides are between spouses or romantic or sexual partners, and these crimes usually take place at home. Attackers who commit murder-suicide in public are far more brazen and unusual. Most suicide terrorists believe they will be honored and celebrated as “martyrs” after their deaths and, sure enough, terrorist organizations produce martyrdom videos and memorabilia so that other desperate souls will volunteer to blow themselves up.

Similarly, rampage shooters have often been captivated by the idea that they will become posthumously famous. “Isn’t it fun to get the respect that we’re going to deserve?” the Columbine shooter Eric Harris remarked. He had fantasized with his fellow attacker, Dylan Klebold, that the filmmakers Steven Spielberg and Quentin Tarantino would fight over the rights to their life story.

Although we can only speculate, Adam Lanza’s decision to target elementary school children in Newtown, Conn., may have been a calculated attempt to get as much attention as possible. Despite misconceptions to the contrary, many mentally ill people are quite capable of staging their attacks for symbolic effect. In 2002, the Washington-area snipers John Allen Muhammad and Lee Boyd Malvo shot a middle schooler, then taunted the police with a note that said “Your children are not safe anywhere at any time.” Mr. Lanza may have realized that the only thing that generates more attention than killing random innocent adults is killing random innocent children.

It is tempting to look back at recent history and wonder what’s wrong with America — our culture and our policies. But underneath the pain, the rage and the desire to die, rampage shooters like Mr. Lanza are remarkably similar to aberrant mass killers — including suicide terrorists — in other countries. The difference rests in how they are shaped by cultural forces and which destructive behaviors they seek to copy. The United States has had more than its share of rampage shootings, but only a few suicide attacks. Other countries are regularly plagued by suicidal explosions, but rarely experience a school shooting.

I can’t help but wonder about Eric Harris, Dylan Klebold, Seung-Hui Cho and Adam Lanza. If they had been born in Gaza or the West Bank, shaped by terrorist organizations’ hateful propaganda, would they have strapped bombs around their waists and blown themselves up? I’m afraid the answer is yes.

Adam Lankford, an assistant professor of criminal justice at the University of Alabama, is the author of the forthcoming book “The Myth of Martyrdom: What Really Drives Suicide Bombers, Rampage Shooters, and Other Self-Destructive Killers.”

A version of this op-ed appears in print on December 18, 2012, on page A35 of the New York edition with the headline: What Drives Suicidal Mass Killers. Today's Paper|Subscribe